Fragrance-releasing devices are well known and commonly used in household and commercial establishments to provide a pleasant environment for people in the immediate space. Further, aroma-driven experiences are well recognized to improve or enhance the general mood of individuals. In some instances, fragrances may trigger memories of experiences associated with the specific scent. Whether it is providing a pleasant environment, affecting a general demeanor, or triggering a nostalgic memory, a steady, long-lasting release of fragrance will ensure consumer and customer satisfaction.
Fragrance-release devices based on passive diffusion are limited in their product-use by a finite supply of the fragrance and its evaporation rate from a surface. In some examples, the fragrance-release device is designed to carry the fragrance liquid within its architecture so that the fragrance supply is finite and determined by the size of the fragrance-release device.
The evaporation rate of fragrance from the fragrance-release device is determined, at least in part, by the composition of the fragrance, where compositions containing more volatile compounds (e.g. “top” notes) will evaporate faster than those with less volatile compounds (e.g. “base” notes), and the temperature of the fragrance-release device. A fragrance composition determines its character. As a result, changing the composition of the fragrance may affect the character. The release rate profile of fragrance is generally strong (more intense) at the beginning of product use, followed by decreasing intensity over time. In some instances, the initial fragrance release is too strong and the fragrance release time is too short. For these fragrances, there is a need to modulate the release of fragrance from the fragrance-release device to provide a steady and long-lasting fragrance release without changing the fragrance load and character.
One method of enhancing the transfer of scent from a fragrance-release device into the surrounding environment is to apply heat. Heat may serve to increase the evaporation rate of volatile compounds from a fragrance-release device, especially in the later stages of use when lower levels of fragrance remain. Heating a fragrance-release device may also provide more complete release of fragrance by fully vaporizing any remaining volatile compounds at a rate that is still detectable by a person in the vicinity of the device. However, heating a fragrance-release device may lead to degradation or disintegration of the fragrance-release device. Also, without proper control over the rate of scent release, heating a fragrance-release device may lead to undesirably strong scents or early depletion of the fragrance reservoir.
Specifically there is a need to temper the release of fragrance compounds in heated fragrance-release devices. A fragrance-release device must not only control the release of scent into the surrounding environment, but also resist deterioration and disintegration under thermal stress.